A pupil finds the mean of 0, 3, 6, 7 and 9 and answers 6.25. Which statement identifies the mistake in this mean calculation?
A zero counts as a value, so the total 25 must be divided by 5, giving a mean of 5.✓Правильный ответ
The total should be 26, so the mean is 5.2.
A zero cannot appear in a data set, so no mean can be found.
The mean should be 6, because 6 is the value that sits centrally in the ordered list.
Объяснение
The five values total 0 + 3 + 6 + 7 + 9 = 25, and there are 5 values because a recorded zero is a genuine observation, so the mean is 5. Dividing by 4 treats the zero as though nothing had been recorded, which shrinks the count while leaving the total unchanged and pushes the result up to 6.25.